/**
    * This file Copyright (c) 2010-2010 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.templatingcomponents.jsp;
  
  import info.magnolia.cms.beans.config.ServerConfiguration;
  import info.magnolia.cms.core.AggregationState;
  import info.magnolia.context.MgnlContext;
  import info.magnolia.module.templatingcomponents.AuthoringUiComponent;
  import org.apache.commons.collections.EnumerationUtils;
  
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.tagext.JspFragment;
  import javax.servlet.jsp.tagext.SimpleTagSupport;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  import java.util.StringTokenizer;
  
  /**
   * @author gjoseph
   * @version $Revision: $ ($Author: $)
   */
  public abstract class AbstractTag extends SimpleTagSupport {
  
      public void doTag() throws JspException, IOException {
          final ServerConfiguration serverConfiguration = ServerConfiguration.getInstance();
          final AggregationState aggregationState = MgnlContext.getAggregationState();
          final AuthoringUiComponent uiComp = prepareUIComponent(serverConfiguration, aggregationState);
  
          uiComp.render(getJspContext().getOut());
  
          try {
              doBody();
          } finally {
              uiComp.postRender();
          }
      }
  
      protected void doBody() throws JspException, IOException {
          final JspFragment body = getJspBody();
          if (body != null) {
              body.invoke(null);
          }
      }
  
      /**
       * Validate parameters and return a ready-to-output instance of an AuthoringUiComponent.
       */
      protected abstract AuthoringUiComponent prepareUIComponent(ServerConfiguration serverCfg, AggregationState aggState) throws JspException, IOException;
  
      // ---- utility methods to convert parameters ----
  
      /**
       * Converts (split) a single comma-separated string, or returns a copy of the given collection or String array.
       */
      protected List<String> mandatoryStringList(Object attrValue, String attributeName) throws JspException {
          if (attrValue == null) {
              throw new JspException(attributeName + " is mandatory and must a comma-separated String or a Collection<String> instance. No value passed, or passed value was null.");
          }
          if (attrValue instanceof String) {
              return split((String) attrValue);
          } else if (attrValue instanceof Collection) {
              return new ArrayList<String>((Collection) attrValue);
          } else if (attrValue instanceof String[]) {
              return Arrays.asList((String[]) attrValue);
         }
 
         throw new JspException(attributeName + " must a comma-separated String or a Collection<String> instance. Passed value was a " + attrValue.getClass().getSimpleName() + ".");
     }
 
     protected List<String> split(String s) {
         if (s == null) {
             return Collections.emptyList();
         }
         final StringTokenizer st = new StringTokenizer(s, ",");
         return EnumerationUtils.toList(st);
     }
 }